Because that is vacuum-packed, to teach you two ways, 1. You first upside down, and then shake your hand (be careful to break oh)! You can open it. 2. with a knife in the cover of the perimeter pry, you will hear a very small sound, and then you can open it, it is best to use a towel to cover the open, friction can save energy! This method can also be used for other glass bottles!